Abstract

In this letter, we present a technique for the deposition of inks, organic polymers and solid particles, using a fluid ejector. The ejector design is based on a flextensional transducer that excites axisymmetric resonant modes in a clamped circular membrane. It is constructed by bonding a thin piezoelectric annular ring to a thin, edge supported, circular membrane. Liquids or solid particles are placed behind one face of the membrane which has a small orifice (50–200 μm diam) at its center. By applying an ac signal across the piezoelectric element, continuous or drop-on-demand ejection of photoresist (Shipley Microposit S1400-21, S1400-27, S1805, and S1813), oil-based ink, water, or talcum powder has been achieved. Successful deposition of photoresist has been accomplished without spinning, and thus without waste. Patterning of 10 μm features, by baking, exposure, and developing, has revealed no defects in the deposition process. A boundary integral method was used to numerically simulate drop formation from the vibrating orifice. Simulations have been used to optimize ejection performance.